Magic of bird songs decoded

Washington, March 18 (IANS) “If music be the food of love, play on,” wrote the immortal bard. Perhaps this is nowhere more conspicuously true than of the little songs birds sing. They trill and warble so joyously, serenading their ladyloves, that it is only a matter of time before they win them over with the magic of their sonorous notes.

Researchers, long fascinated by the melodious ritual, have discovered some of its intricacies and how the brain develops and responds to such social cues - in both birds and humans.

The discovery paves the way to study how complex brain circuits recognise cues, especially acoustic signals, and how they acquire this capacity, questions of potential relevance to humans.

Findings of the study, which appear in the March issue of the journal PLoS Biology, could shed light both on normal development and on disabling disorders of social interactions, such as autism.

Scientists have known that monogamous species like male zebra finches modify their tune when they have courtship on their minds, with a prospective or lifelong mate.

The birds sing faster and produce syllables with less variability in pitch as they dance about the object of their affection. Scientists haven’t actually known if the females detect and discriminate between the tunes. The current study reveals that they do.

The researchers also found that female finches have an ear for detail: They were especially sensitive to the degree of variability in the pitch of notes, strongly preferring directed songs least variable in pitch.

This finding is provocative, the researchers say, because recent evidence has shown that pitch variability in male song is controlled by a specialized forebrain-basal ganglia circuit known as the anterior forebrain pathway.

“It is interesting that the neural circuit responsible for the learning of song in juveniles may also be responsible for making the adult male’s song more attractive” said Sarah C. Woolley and co-author Allison J. Doupe of the University of California.

This data revealed that one brain area responded to whether songs were directed or undirected, while a second area responded to whether songs were familiar or unfamiliar.